The IRIX 6.5 regex.h header file defines REG_STARTEND, but the feature does
not appear to work. Since REG_STARTEND is required for proper functioning
of git-grep, set NO_REGEX and use the alternative regex libraries in compat/
Signed-off-by: Brandon Casey <casey@nrlssc.navy.mil> Signed-off-by: Junio C Hamano <gitster@pobox.com>